Pulmonary resuscitation (CPR) is a resuscitation measure taken for cardiac and respiratory arrests. That is, external chest compressions to form a temporary artificial circulation, rapid electrical defibrillation to turn back the ventricular fibrillation (VF), to promote the heart to restore the voluntary beat; the use of artificial respiration to correct hypoxia, and efforts to restore voluntary breathing.
I. Adult basic life support (ABLS)
(I) Indications for basic life support (BLS)
1.Respiratory arrest
Many causes can cause respiratory arrest, including drowning, stroke, airway foreign body obstruction, smoke inhalation, epiglottitis, drug overdose, electric shock, asphyxia, trauma. and coma from various causes. One minute after primary respiratory arrest, the heart will also stop beating, at which point an already oxygenated blood supply will still be available for several minutes of doing chest compressions. When respiratory arrest or insufficient spontaneous breathing, it is very important to ensure a clear airway and perform emergency artificial ventilation to prevent cardiac arrest from occurring. In early cardiac arrest, an ineffective “sigh-like” respiratory maneuver may occur, but it should not be confused with an effective respiratory maneuver.
2.Cardiac arrest
In addition to the above causes of respiratory arrest and consequently cardiac arrest, there are also acute myocardial infarction, severe arrhythmias such as ventricular fibrillation, heavy cranial injury, massive blood loss due to rupture of the heart or large blood vessels, drug or toxic poisoning, and severe electrolyte disorders such as hyperkalemia or hypokalemia. In cardiac arrest, the blood circulation stops and all important organs lose oxygen supply. If the blood supply cannot be restored in a few minutes, irreversible damage will occur to the brain and other vital organs.
(II) On-site resuscitation procedures
The judgment phase of BLS is extremely critical, and only after accurate judgment can the patient receive further CPR (correction of position, opening of airway, manual ventilation or chest compressions). The judgment time is required to be very short and rapid.
1. Judgment of patient response
When the witness, such as non-medical personnel, the patient does not breathe, does not cough, and does not respond to stimulation (such as blinking or limb movement, etc.), respiratory arrest can be judged, and CPR is started immediately (as in Figure 1).
2.Start EMSS
Start CPR immediately after pulling the emergency phone. for drowning, serious trauma, poisoning, CPR should be started before calling for help, and a doctor should provide initial instructions for treatment over the phone. If there are more than one person present, initiating EMSS and CPR should be done simultaneously (as in Figure 2).
3. Patient position
The patient must be placed supine on a firm flat (floor) surface. If the patient is to be turned, the neck should always be kept on the same axis as the trunk. If the patient has head and neck trauma or is suspected of having a neck injury, the patient should be moved only when absolutely necessary; inappropriate moving of a patient with spinal cord injury may result in paraplegia. Place both upper limbs on both sides of the body, this position is more suitable for CPR (Figure 3).
4.Open airway
The most common cause of airway obstruction is the backward fall of the tongue root, because the tongue is attached to the jaw, and the loss of consciousness causes the jaw and tongue to fall back in patients with muscle relaxation. At this point, the jaw is lifted up and the tongue leaves the pharynx, and the airway can be opened (Figure 4). If there is no neck trauma, the airway can be opened by tilting the head and lifting the chin, and the foreign body and vomit in the patient’s mouth can be removed, and liquid secretions in the mouth can be removed with finger sleeves or finger-wrapped gauze. When removing solid foreign body, press open the jaw with one hand and hook out the solid foreign body with the index finger of the other hand.
(1) Tilting head and lifting chin method
To complete the head tilting action, one hand should be placed on the patient’s forehead and the forehead should be pushed backward with the palm of the hand so that the head is tilted backward, and the fingers of the other hand should be placed at the chin bone and the chin should be lifted upward so that the teeth are closed and the chin is lifted upward, do not press the soft tissues of the jaw with force, otherwise it may cause airway obstruction, and avoid lifting the jaw with the thumb (as in Figure 5).
(2) Jaw resting method
Place your hands on both sides of the patient’s head, support your elbows on the plane where the patient is lying, hold the mandibular angle and forcefully hold the jaw upward, if the patient tightly closes the lips, use your thumbs to separate the lips from the mouth. If mouth-to-mouth breathing is required, hold the jaw upward continuously and press the patient’s nostrils with the cheeks (Figure 6).
5. Artificial respiration
(1) Check breathing
After opening the airway, first put the ear near the patient’s mouth and nose to feel whether there is breath, then observe whether there is heaving action of the chest, and finally listen carefully for the sound of airflow exhalation, and place a little cotton at the mouth and nose to clearly observe whether there is airflow. If there is no above signs can be determined no breathing, the judgment and evaluation time should not exceed 10 seconds. Most patients in respiratory or cardiac arrest are not breathing. Occasionally, patients with abnormal or irregular breathing, or dyspnea with obvious signs of airway obstruction, may resume effective breathing after opening the airway. If no respiration or abnormal respiration is found after opening the airway, artificial ventilation should be implemented immediately, or if it is uncertain whether the ventilation is abnormal or not.
(2) Mouth-to-mouth breathing
Mouth-to-mouth breathing is a fast and effective method of ventilation, and the oxygen in the exhaled gas (containing 16% ~ 17%) is sufficient to meet the patient’s needs. During artificial respiration, ensure the airway is open, pinch the patient’s nostrils to prevent air leakage, the first responder covers the patient’s mouth with the mouth and lips in a sealed position, blow slowly, each blow should last more than 2 seconds, ensure that the chest rises when blowing, and the ventilation frequency should be 10 ~ 12 times/min. In order to reduce the occurrence of gastric distension, for most adults in the blowing l0 ml / kg (about 700 ~ 1000 m1) tidal volume given for more than 2 seconds can provide sufficient oxygenation (Figure 7).
(3) Mouth-to-nose breathing
Mouth-to-nose breathing should be recommended when it is difficult to perform mouth-to-mouth breathing, especially when the patient’s teeth are closed and he cannot open his mouth and lips are traumatized. Mouth-to-nose respiration is best applied to drowning patients because the rescuer’s hands should hold the drowning patient’s head and shoulders, and mouth-to-nose respiration can be performed as soon as the patient’s head is exposed to the water (Figure 8).
(4) Mouth-to-mask breathing
With a transparent one-way valve mask, the first responder can blow the exhalation into the patient’s lungs to avoid direct contact with the patient’s mouth and lips, and some masks have an oxygen interface to supply oxygen while breathing from the mouth to the mask. When ventilating with the mask, the mask is pressed against the patient’s face with both hands to strengthen its closure for better ventilation effect (Figure 9).
(5) Balloon mask device
The use of balloon mask can provide positive pressure ventilation, and the general balloon inflation capacity is about 1000 m1, which is sufficient to fully inflate the lungs, but it is difficult to ensure that the balloon is not leaking during first aid, so it is easy to have insufficient ventilation when resuscitating a single person, and the effect is better when resuscitating a double person. When operating in pairs, one person should press the mask and one person should squeeze the skin bag.
6.Circulatory support
(1) Pulse check: for every 1 minute delay in electric defibrillation in VF patients, the defibrillation success rate is reduced by 7% ~ 10%. Since the enactment of resuscitation standards in 1968, pulse check has been the main criterion for determining whether the heart is beating, but only 15% of the population can complete a pulse check within 10 seconds. If carotid artery examination is used as a diagnostic tool, its specificity is only 90%, sensitivity (accurately recognizing patients with a pulse and no cardiac arrest), only 55%, and overall accuracy is only 65% with an error rate of 35%.
Based on these results and in accordance with the International CPR Guidelines 2000, this guideline recommends that lay EMTs no longer be required to check for carotid pulsation as a diagnostic step before performing CPB, but only for circulatory signs. However, for professional first responders, pulse checking is still required to confirm the circulatory status, and the time required to check the carotid artery should be less than 10 seconds.
(2) Checking circulatory signs
Checking circulatory signs refers to evaluating the patient’s normal breathing, coughing, and motor response to emergency ventilation. Non-specialists should carefully identify normal breathing and near-death breathing by looking, listening and sensing the patient’s breathing and other body movement functions. For professional emergency personnel, when checking the circulatory signs, they should check the carotid artery pulsation on one hand and observe the breathing, coughing and movement on the other hand. Professionals should be able to identify normal breathing, near-death breathing, and other forms of ventilation in cardiac arrest, and should not take more than 10 seconds to evaluate. If it is not certain whether there is circulation, then chest compressions should be started immediately. in patients over 1 year old, the carotid artery is easier to reach than the femoral artery, and the method of reaching it is that after the patient tilts his head, the first-aider presses the forehead with one hand and finds the trachea with the index and middle fingers of the other hand, and the carotid artery can be reached by sliding the two fingers down into the groove between the trachea and the muscles on the side of the neck (as in Figure 10).
(3) Extrathoracic compressions
External chest compressions during CPR provide a series of pressures in the lower 1/2 of the sternum, which can provide an aerobic blood supply to the brain and other vital organs by increasing intrathoracic pressure or directly squeezing the heart to produce blood flow, and supplemented by appropriate artificial respiration, which facilitates electrical defibrillation.
The International Guidelines for Cardiopulmonary Resuscitation 2000 specify a compression frequency of 100 compressions/min. In single-person resuscitation, the actual number of compressions should be slightly less than 100/min because of the need for artificial ventilation between compressions. For these reasons, Guideline 2000 stipulates that before tracheal intubation, whether single or double CPR, the compression/ventilation ratio is 15s2 (15 continuous compressions followed by 2 puffs), and after tracheal intubation, compressions and ventilation may not be synchronized, when a ratio of 5s1 is available.
Note: BLS guidelines have stipulated that the compression/ventilation ratio for single CPR is 15s2; for double CPR, the compression/ventilation ratio is 5s1. Because 15 uninterrupted compressions produce higher coronary pressure than 5 uninterrupted compressions, after each compression is stopped due to ventilation, it takes several consecutive compressions before the cerebral and coronary perfusion pressure reaches the level before the ventilation is stopped.
Techniques of chest compressions.
① Fix the appropriate compression position and touch the lower edge of the thorax of the patient with the fingers close to the side of the rescuer.
② Slide the fingers toward the midline to find the rib and sternal junction.
③ Place the palm of the other hand against the lower part of the patient’s sternum immediately adjacent to the finger, and overlap the moving palm of the original finger on the back of this hand, ensuring that the long axis of the root of the palm is consistent with the long axis of the sternum, ensuring that the palm is pressed with full force on the sternum, which can avoid rib fractures, and do not press on the saber process (as in Figure 11A ~ C).
④ Whether the fingers are straight or crossed together, they should leave the chest wall and the fingers should not be pressed downward with force.
To ensure effective compressions.
① Elbows straight, upper limbs in a straight line, shoulders square to hands to ensure that the direction of each compression is perpendicular to the sternum. If the direction of force during compression is not perpendicular, part of the compression force is lost, affecting the compression effect (e.g., Figure 11D).
② For normal-shaped patients, the amplitude of compression is 4 ~ 5 cm. In order to achieve effective compression, the amplitude of compression can be increased or decreased according to the size of the body, and the most ideal compression effect is that the carotid or femoral artery pulsation can be palpated. However, the compression force is based on the amplitude of compression, not only on the pulse.
③ After each compression, relax the hands so that the sternum returns to the position before the compression, and blood can flow back to the chest cavity during this period. Do not leave the chest wall when relaxing, so that the position of the hands remains fixed on the one hand, and on the other hand, reduce the impact of the sternum itself reset to avoid fracture.
④ Effective cerebral and coronary perfusion pressure can be produced when the compression and relaxation time is 50% each in one compression cycle.
⑤ During 15 compression cycles, keep the position of both hands fixed, do not change the position of the hands, and do not remove the hands from the chest wall; after each compression, allow the thorax to return to its original position before performing the next compression.
(4) Single or double CPR
① Judgment: determine whether the patient is unresponsive (pat or lightly shake the patient and call out loudly).
(ii) Timely activation of EMSS according to the actual local situation.
③ Airway: place the patient in an appropriate position and open the airway by tilting the head and lifting the chin method or jaw resting method.
④ Breathing: Determine whether there is no breathing or insufficient ventilation. If the patient is unresponsive but breathing and there is no spinal injury, place the patient in a lateral position and keep the airway open. If the patient is unresponsive and not breathing, place the patient in a flat supine position and start artificial respiration and chest compressions at a compression/ventilation ratio of 15s2. When opening the airway for ventilation, look for foreign bodies in the pharynx and remove them immediately if present.
⑤ Circulation: check circulatory signs, after starting ventilation, observe the response to initial ventilation, check the patient’s breathing, cough, presence or absence of activity, professionals should also check carotid pulsation (no more than 10 seconds), if there are no circulatory signs, start chest compressions immediately. (ii) After opening the airway, blow slowly for 2 times, with each ventilation lasting 2 seconds, and then perform 15 chest compressions, completing 4 cycles of 15 s2 compressions/ventilation.
(vi) Re-evaluation: after performing 4 compression/ventilation cycles, check the circulatory signs again, and if there are still no circulatory signs, re-perform CPR.
Double CPR.
In double CPR, one person is located beside the patient and presses the chest, while the other person is still located on the side of the patient’s head, keeping the airway open, monitoring the carotid artery pulsation, evaluating the effect of compressions, and performing manual ventilation, with a compression frequency of 100 times/minute and a compression/ventilation ratio of 15s2, and when the person who presses the chest is fatigued, the two people can switch with each other.
(5) Recovery position (lateral position)
For patients who do not respond but have respiratory and circulatory signs, the recovery position should be adopted. Because, if the patient continues to take the supine position, the patient’s tongue, mucus and vomit may obstruct the airway, and such situation can be prevented by taking the lateral position.
7.Identification and treatment of foreign body obstruction (FBAO)
Complete airway obstruction is an acute condition that can lead to death within minutes if left untreated. Unresponsive patients can have airway obstruction due to intrinsic factors (tongue, epiglottis) or extrinsic factors (foreign body). The tongue falling backward and blocking the airway opening and the epiglottis can also block the airway opening, both of which can cause airway obstruction, which is the most common cause of upper airway obstruction in loss of consciousness and cardiac and respiratory arrest. In patients with head and facial injuries, especially those with loss of consciousness, blood and vomitus can block the airway and airway obstruction can occur.
(1) Causes of FBAO
FBAO should be considered in any patient with sudden respiratory arrest, especially in young patients with sudden respiratory arrest, cyanosis and loss of consciousness without any cause. In adults, FBAO usually occurs when eating. Meat is the most common cause of obstruction, and many other foods can cause erratic choking in adults or children. The occurrence of erratic choking is mainly caused by trying to swallow large pieces of difficult-to-chew food. Elderly patients with elevated blood alcohol levels from alcohol consumption, dentures, and swallowing difficulties are also prone to FBAO.
(2) Recognition of FBAO
Identification of foreign body obstruction in the airway is the key to successful resuscitation. Therefore, it is important to differentiate it from other emergencies, which include deficiency, stroke, heart attack, convulsion or seizure, drug overdose, and other factors causing respiratory failure, which are treated with different principles. Foreign bodies can cause partial or complete airway obstruction. In partial obstruction, the patient can still have gas exchange, and if gas exchange is good, the patient can cough hard, but wheezing occurs when coughing stops. As long as gas exchange is good, the patient should be encouraged to continue coughing and breathing on his own. First responders should not interfere with the patient’s efforts to remove the foreign body on their own, but should guard and monitor the patient and initiate EMSS if the partial airway obstruction remains unrelieved.
Patients with FBAO may start with poor gas exchange or may start with good gas exchange but gradually deteriorate. Signs of poor gas exchange include a weak and ineffective cough, high-pitched noise on inspiration, increased dyspnea, and cyanosis.
Patients with complete airway obstruction cannot speak, cannot breathe or cough, may grasp the neck with both fingers, and gas exchange is lost, so this must be clearly identified. If a patient shows signs of complete airway obstruction and cannot speak, there is a complete airway obstruction and must be treated immediately. When the airway is completely obstructed, the patient’s oxygen saturation drops quickly because the gas cannot enter the lungs, and if the obstruction is not relieved soon, the patient will lose consciousness or even die soon.
(3) Release of FBAO
Abdominal shock method (Heimlich method)